GOALS-JWST: Revealing the Buried Star Clusters in the Luminous Infrared Galaxy VV 114

Linden, Sean T.; Evans, Aaron S.; Armus, Lee; Rich, Jeffrey A.; Larson, Kirsten L.; Lai, Thomas; Privon, George C.; Vivian, U.; Inami, Hanae; Bohn, Thomas; Song, Yiqing; Barcos-Munoz, Loreto; Charmandaris, Vassilis; Medling, Anne M.; Stierwalt, Sabrina; Diaz-Santos, Tanio; Boker, Torsten; van der Werf, Paul; Aalto, Susanne; Appleton, Philip; Brown, Michael J. I.; Hayward, Christopher C.; Howell, Justin H.; Iwasawa, Kazushi; Kemper, Francisca; Frayer, David T.; Law, David; Malkan, Matthew A.; Marshall, Jason; Mazzarella, Joseph M.; Murphy, Eric J.; Sanders, David; Surace, Jason
2023
ASTROPHYSICAL JOURNAL LETTERS
DOI
10.3847/2041-8213/acb335
We present the results of a James Webb Space Telescope NIRCam investigation into the young massive star cluster (YMC) population in the luminous infrared galaxy VV 114. We identify 374 compact YMC candidates with signal-to-noise ratios >= 3, 5, and 5 at F150W, F200W, and F356W, respectively. A direct comparison with our HST cluster catalog reveals that similar to 20% of these sources are undetected at optical wavelengths. Based on yggdrasil stellar population models, we identify 17 YMC candidates in our JWST imaging alone with F150W - F200W and F200W - F356W colors suggesting they are all very young, dusty (A(V) = 5-15), and massive (10(5.8) < M-circle dot < 10(6.1)). The discovery of these "hidden" sources, many of which are found in the "overlap" region between the two nuclei, quadruples the number of t < 3 Myr clusters and nearly doubles the number of t < 6 Myr clusters detected in VV 114. Now extending the cluster age distribution (dN d tau (sic) t(gamma)) to the youngest ages, we find a slope of gamma = -1.30 +/- 0.39 for 10(6) < tau(yr) < 10(7), which is consistent with the previously determined value from 10(7) < tau(yr) < 10(8.5), and confirms that VV 114 has a steep age distribution slope for all massive star clusters across the entire range of cluster ages observed. Finally, the consistency between our JWST-and HST-derived age distribution slopes indicates that the balance between cluster formation and destruction has not been significantly altered in VV 114 over the last 0.5 Gyr.